When people live plural marriage, only one of the marriages is legal. The other marriages are spiritual, and thus--when it comes to the law--could be compared to trysts or common-law marriages, which are commonplace in this country. But people engaged in affairs or living together without the benefit of marriage don't fear of criminal reprisal. People living plural marriage do. That's because of the widespread assumption that polygamy is a crime and polygamists are criminals, even in this day of "consenting adults." The Senate Judiciary Committee, in "stacking the witness list" seems to buy into this assumption.
It is prejudicial to prosecute people for having more than one sexual partner. The inference that all polygamists are criminals, then, takes on the character of an ethnic slur. It's like saying that all African-Americans are lazy or that all Jews are greedy or that all Muslems are terrorists. After a half-century of civil rights enlightenment, one would hope for a more intelligent and fair-minded approach from the great bastion of democracy.